An antitumor drug is orally or intravenously administered for treating the special neoplastic tissues. In that case, as the antitumor drug diffuses into the whole body, the concentratration of the antitumor drug in the special neoplastic tissues is lowered, and hence the sufficient treatment effect cannot be obtained as well as undesirable side effects to the living body sometimes occur.
For overcoming these problems, it has been proposed to directly administer a preparation composed of an antitumor drug carried on a carrier having low toxicity such as albumin, synthetic high molecular materials, fats and oils, etc., into a lymph vessel or blood vessels for internal organs.
However, since many important antitumor drugs are water-soluble or sparingly soluble in oils, it is generally difficult to produce preparations of antitumor drugs carried on fats and oils, which are used for the above-described administration method. In fact, as such preparations which are practically used, there is only a preparation of epitiostanol dissolved in sesame oil.
The inventors previously investigated the method of producing the preparations of sparingly oil soluble or water soluble antitumor drugs, which can be used for the above-described administration method and succeeded in producing the preparations of compositions composed of the antitumor drugs, solubilizing adjuvants in oily vehicles such as crown ether, etc., and fats and oils (or an unsaturated higher fatty acid alone) (Japanese Patent Publication (Unexamined) No. 124714/'83).